The results of \textit{ab-initio} $\mathbf{R}$-matrix calculations display profound deviations from Mulliken's rule in the continuum electronic structure of CaF. In the $1-D$ effective potential for the electronic motion, a shape resonance induces a crossover from short-range Mulliken-type dynamics to long-range dipole-mediated dynamics. This effect is visible in the scattering matrix as well as the photoionization cross-sections and photoelectron anisotropies. The non-Mulliken behavior can be exploited by $l$-selective detection of Rydberg dynamics and spectra, revealing the $l$-decomposition of molecular eigenstates.